A broad low pressure system that slammed the mid-Atlantic and Northeastern U.S. this weekend with flooding, massive waves, and wind gusts of up to 93 mph was still hurling rough seas and storm tides at the U.S. East Coast on Monday. Such widely-varied locations as coastal Florida and New Jersey were experiencing high water, beach erosion, raging surf and minor coastal flooding. Officials were warning people to stay off the beach and away from riled seas as crews rushed to clear debris.

The storm gained extreme intensity that was likely peaked by a number of climate change related factors including warmer than normal sea surface temperatures, a blocking high over Greenland that was likely impacted by a recent polar warming event, and higher sea levels resulting increasingly severe tidal flooding during the storm’s peak.

(A massive low pressure system that knocked out power to hundreds of thousands and flooded the Northeast coastline this weekend still churned off the U.S. East Coast on Monday — lashing shores with rough surf and minor flooding. Image source: Earth Nullschool.)

Inland, nearly a quarter million people were still without power from Virginia through Maine — down from a high of around two million at the weekend storm’s peak. However, utilities are saying that it may take days to fully restore power to some locations. As repair crews were scrambling, another major storm was starting to gather over the Great Plains — with a high pressure system across Florida drawing very moist air from over a much warmer than normal Gulf of Mexico and into the developing storm’s circulation.

Over the next 24 hours, the new storm is projected to track eastward — crossing to the Ohio River Valley region by late Tuesday. On Wednesday, the low will transition energy into a developing storm off Virginia and the Outer Banks. This low is then expected to rapidly intensify as it moves northward — developing strong onshore winds with gusts of 45-65 mph crossing coastal Delaware, New Jersey, Long Island, Connecticut, Rhode Island and Massachusetts by late Wednesday and into early Thursday.

(Models show another powerful low pressure system battering the Northeast Coast with 45-65 mph winds by early Thursday. Image source: Tropical Tidbits.)

Presently, the storm is not expected to be as strong as the massive system that slammed the Northeast and Mid-Atlantic this weekend. However, gale force to storm force gusts are presently predicted, and forecast storm strength has been trending toward higher intensity in recent model runs.

In addition, climate change related factors like a warmer than normal Gulf of Mexico, much warmer than normal sea surface temperatures in the Gulf Stream, higher sea levels, and a large blocking high over Greenland are contributing to this most recent storm’s expected intensity. With hundreds of thousands still recovering from this weekend’s historic storm, and with so many factors now in play that could serve to further spike a new storm’s intensity above those presently expected, this is a developing situation that bears watching.

A broad region across the northeast from D.C. to Maine are now experiencing wind gusts of 50 to 80 mph or more with local power outages and downed lines reported over a broad region. The gusts are so strong and widespread that diverse locations all throughout the Northeast are seeing instances of toppled trees, damage to structures and falling limbs. In Chambersburg, PA, the raging gusts tipped over a school bus.

(A broadening storm is lashing most of the Northeastern U.S. with gale and hurricane force winds even as a places like Boston face massive waves and record storm surge flooding. Image source: Earth Nullschool.)

But what is, perhaps, more concerning is the fact that this storm is still gathering strength. And due to a blocking high over Greenland, the storm — dubbed Riley — is likely to only slowly move off-shore. So its impacts will tend to persist for multiple high tide cycles even as its circulation broadens and it generates an east-to-west fetch of gale to hurricane force winds stretching over a 400 to 600 mile region of ocean and driving directly toward the Northeast and East Coasts.

This will enable a long-lasting storm surge that will generate serious flooding for hundreds of miles of coastline. And on top of that surge, towering waves will relentlessly batter the coast throughout Friday and Saturday. Already the flooding has become quite severe for a number of locations. But the situation is likely to get worse before it gets better. With the worst impacts expected at high tide late tonight.

Scenes like these bring back recollections of Sandy. And like Sandy, the present cyclone has been influenced in a number of ways by human-caused climate change.

The storm’s historic intensity was first fed by a large plume of moisture issuing off a much warmer than normal Gulf of Mexico. Instability, driven by a deep diving trough, formed a low sweeping over the north-central U.S. that then tapped this high volume of moisture. The latent heat in the moisture enabled stronger than normal convection which helped to spike the storm’s early intensity.

(Extremely warm sea surface temperatures both in the Gulf of Mexico and off the U.S. East Coast are helping to fuel the present storm’s record intensity. This is just one of the climate change associated factors contributing to the present storm. Image source: Earth Nullschool.)

Off shore, the Gulf Stream waters are also far warmer than normal. Ranging as high as 9 degrees Celsius above average, this abnormal heat helped to fuel a second plume of moisture and instability. And as these two areas of storminess merged, they rapidly bombed out to high intensity even as their area of storm wind circulation broadened.

To the north, a recent (climate change driven) polar warming event has generated a kind of train wreck in the upper level winds that typically hurry storm systems along. As a result of this train wreck, a blocking high over Greenland is preventing this heat-amplified storm from tracking eastward. Over the next 48 hours, this block will allow a massive pile of water and towering waves to relentlessly hammer the Northeastern and Eastern Coasts of the U.S.

(Large waves and long fetch which is predicted to be generated by this storm on Saturday could produce serious and wide-ranging impacts all up and down the Eastern Seaboard from Hatteras to Portland and points northward. Image source: Earth Nullschool.)

Presently, this storm is expected to produce the second 1 in 100 year flood event that the Boston area has seen in the past year. Under typical climate variability, the likelihood of seeing back-to-back events of this kind would be 1 in 10,000. However, due to the influences of human-caused climate change, the potential for extreme weather events like the one we are presently enduring are greatly enhanced.

The Ohio River Valley is now reeling from the worst flooding event of the past 20 years. Yet one more major event fueled by disruptions to the Earth’s atmosphere facilitated by human-caused climate change. But with another serious plume of moisture issuing from the warmer than normal waters of the Gulf of Mexico, more heavy rains are heading toward a storm-battered Central U.S.

(One more big moisture plume arises from a warmer than normal Gulf of Mexico. It will help to fuel a major storm system that is expected to impact a large swath of the U.S. for most of this week. Image source: Earth Nullschool.)

The set-up is similar to previous events of the past two weeks. A strong high pressure system over the Northeast is pulling a heavy load of moisture from a much warmer than normal Gulf of Mexico. Sea surface temperatures there, according to Earth Nullschool reanalysis, range from less than 1 C warmer than normal in the southern Gulf to as much as 5 C warmer than normal in the northern Gulf. Last week, these warmer than normal sea surfaces helped to fuel record atmospheric moisture levels along with historically heavy rains.

(NOAA composite radar imagery shows observed precipitation totals for the U.S. during the past 14 days. Note that another batch of heavy rains is headed directly for the region that has already been hit the hardest.)

(Very strong northeasterly winds are expected to rake the coasts of Maine and Massachusetts by March 2 according to GFS model forecasts. Image source: Earth Nullschool.)

Though the shape of the present storm is still a bit unclear, it is likely to both further exacerbate already severe flooding over the Central U.S. even as it generates some serious coastal flooding potentials for the Northeast by the end of this week. What is also clear is that a warming polar environment is contributing to these upstream severe weather events by increasing their persistence even as warming ocean surfaces are helping to feed them with larger moisture loads which generates higher potential storm and rainfall intensity.

This rapid intensification will be fueled by a combination of warmer than normal sea surface temperatures off the U.S. East Coast and by the tropical system’s collision with a colder and very deep trough sweeping down from the north. The interaction of trough, storm, and warmer than normal surface water is predicted to generate some record-breaking extreme weather for the U.S. Northeast by Sunday through Monday.

(A 968 mb storm making landfall in Northern New England on Monday would be a record event for October. Image source: Tropical Tidbits.)

As this hybrid storm rockets in from the much warmer than normal ocean, it is expected to bring with it hurricane force wind gusts and extreme one day rainfall amounts for the region. Weather models now show that sustained winds may exceed 60 mph for the New York, Connecticut, Rhode Island, Massachusetts, New Hampshire and Maine coasts. Meanwhile some models are indicating hurricane force gusts of up to 92 mph or higher for the region. Rainfall totals over a rather short time period are also expected to exceed 4 inches over a broad area stretching deep into New York state. It’s worth noting that the system will inject unseasonably warm air into Northern New England. So most of the precipitation associated with the storm is presently expected to fall as rain.

The storm’s associated powerful winds will likely drive a stronger than usual storm surge for a Nor’Easter into coastal areas — with flooding more reminiscent of that of a moderate hurricane. We could also see electricity knocked out for more than a million residents as this potentially record-breaking system moves in.

Headed to New England for the massive nor’easter that will bring very high wind and heavy rain Sunday/Mon. Gusts to hurricane force possible pic.twitter.com/NxWo2ZbNbe

We should also note that the moisture feed bleeding into this particular storm is quite intense. And as with other recent events we could see projected rainfall totals exceeded. This due to a heavier atmospheric moisture load and related intense convection associated with atmospheric temperatures that are now, on average, 1 to 1.2 C warmer than late 19th Century temperatures. And such warmer temperatures, set off primarily by human fossil fuel burning, are now increasing the peak intensity of extreme rainfall events.

As noted in yesterday’s post, the factors involved in the present Nor’Easter are rather odd when considering past contexts. For one, winds will tend to blow from the south. This is indicative of a somewhat off-kilter track when compared to a typical Nor’Easter. In addition, various climate change associated elements like the high amplitude trough related to polar warming, the joining of tropical weather with Arctic-originating weather to generate an overall more intense storm, an enhanced overall convection and related increased winds and rainfall rates, and the fuel provided by warmer than normal sea surface temperatures are all factors related to human-caused climate change.

A Nor’Easter that could trouble the New Jersey, New York, Connecticut, Rhode Island and Massachusetts coasts with 50 mph wind gusts is in the process of forming today. A deep trough produced by a powerful blocking pattern and worsened by eroding Arctic Sea Ice is channeling a low pressure system that is likely to deepen off Cape Hatteras later tonight.

Models show the potential for a 990 mb low pressure forming off the Northeast coast come Wednesday. The result is that tropical storm force winds may bring 7-8 foot water rises (2-3 foot storm surges on top of high tides) to areas already devastated by Hurricane Sandy. Normally, a water rise of this level would result in light to moderate tidal flooding. However, in areas where dunes have been wiped out, sea walls and board walks beaten to bits, this rather moderate storm surge may re-flood some communities still reeling from last week’s disaster.

Tropical storm force winds may again knock out power in some areas still struggling to repair damage from Sandy. 1.3 million homes and businesses remain without power following the storm, down from 8.5 million a week ago. In addition, 1-2 inches of rain along the coast and snowfall in a region from Pennsylvania to Maine may cause further difficulty — especially for those still without power.

Though this storm is likely to be nothing like Sandy, it is a reminder of a new and ominous weather pattern taking shape this winter. According to numerous Arctic researchers, this year’s record sea ice melt is contributing to a powerful negative Arctic Oscillation. This weather condition has produced a strong trough swooping down from the Arctic and through the Eastern United States. The trough is producing numerous storms — one which combined with Hurricane Sandy to form a powerful superstorm. This week, the trough is bringing an early-season Nor’Easter. An odd second-week appearance of a storm that usually forms during winter.

These weather events may well be harbingers for very stormy conditions throughout the winter of 2012 for the US East Coast and Northeast. Jennifer Francis, an Arctic researcher at Rutgers University warned only just a few weeks ago that human climate change and sea ice loss was resulting in a situation that would likely produce a succession of powerful storms this fall and winter.

As the new storm forms off the East Coast, more scientists are affirming climate change’s role in both making Sandy worse and in producing a general climate of increasingly extreme weather. An article written by Dr. Jeff Masters, Dr. Bob Corell, and Dr. Kevin Trenberth entitled Did climate change contribute to Sandy? Yes published in Politico and Reuters yesterday. The article clearly stated that climate change made Sandy worse and warned that unless human carbon emissions are dramatically reduced more and more severe weather is to follow.

Climate scientists broadly agree that the extreme weather we’ve seen over the past few years is exactly what we’d expect to see in a changing climate. And it’s not just Sandy; we’re on track to have the hottest year in more than a century of record-keeping in the continental United States, the country has suffered one of the most crippling droughts in history, as well as one of the worst wildfire years in history. Last year, when Hurricane Irene hit the United States, meteorologists called it “unprecedented,” yet Sandy has already outpaced the damage from Irene.

We’ll probably never know the exact point when the weather stopped being entirely natural. But we should consider Sandy—and other recent extreme weather events – an early taste of a climate-changed world, and a grim preview of the even worse to come, particularly if we continue to pump more carbon pollution from smokestacks and tailpipes up into the atmosphere.

Jeff Masters is a meteorologist and former Hurricane Hunter, he now directs the climate blog WeatherUnderground. Bob Corell is an American climate scientist. Kevin Trenberth is the head of the US National Center for Atmospheric Research. Together, they represent over 150 years of climate science and meteorological experience.

Yesterday, a hurricane that had combined with a nor’easter and then tapped into both the powerful energies of an over-heated Atlantic Ocean and cold Arctic air seeping out through regions once encased in sea ice vented its fury on the New Jersey coastline. All up and down the Jersey Shore, community after community faced a historic storm surge born of a storm made far worse by climate change. A storm whose effects were the worst seen in this region of the US East Coast in 300 years.

Atlantic City seemed to bear the brunt of Sandy’s wrath. As early as Monday morning, the city’s coastal defenses were breached, its sea wall overwhelmed, its boardwalk washed away and its streets and homes subject to the pounding force and rush of storm waves. Residents of the barrier island community found themselves stranded as the rising tide cut off access to their community. Many fled to community storm shelters only to find the rising tide flooding these structures as well. Homes were ripped off their foundations and floated down the street or were swept into the raging Atlantic. At one point, a National Guard unit made a valiant effort to save some of those stranded by the storm. The effort was partly successful, but resulted in the loss and flooding of a number of pieces of military equipment. Overnight, the storm worsened, preventing any access to the storm-ravaged town and forcing its terrified residents to spend a water logged and fearful night alone and without public aid.

Just to the south of Atlantic City, Ocean City also faced Sandy’s terrible wrath. A seven foot water rise inundated the town and flooded its streets. As the water rose, 231 residents made emergency calls for help after refusing to heed evacuation orders. Though 50 persons were moved to escape the raging seas, miraculously no lives were lost. Almost as an after-thought Sandy parted with a 100 foot section of the Ocean City Pier.

Further north along the coast, Point Pleasant waged a valiant battle against rising seas all throughout the day. High waves and pressing tides battered the city’s beleaguered dune line. Finally, as the storm rushed in with the astronomical high tide, the dunes gave way and torrents of water rushed into the town’s streets. The city’s boardwalk was torn to shreds as boats were ripped from their moorings to float into the city where they were finally laid to rest on streets, lawns, or railroad tracks. In some places, water rushed nearly a mile inland. One home, three quarters of a mile from the shore, flooded with more than a foot of ocean water in the first floor driven in by Sandy and the 8 PM high tide.

“I kept asking him [my husband], ‘Should we go on the roof?’ I was really scared,” said Rosemary, as their house flooded. “The force and the speed that the water was pouring down and pouring over, it was scary. It rose so fast. It just kept coming and coming.”

In another part of town, firemen bravely faced the rising waters, slogging through the chest-deep flood to reach stranded residents.

The word New Jersey governor Chris Christie used to describe the wide-spread and far-ranging devastation all up and down the Jersey coast was “unthinkable.”

“The idea … that you see homes in the middle of Route 35 southbound and northbound is just unfathomable,” Christie told reporters at a morning briefing.